<template>
  <div class="xtx-carousel" @mouseenter="stop" @mouseleave="start">
    <ul class="carousel-body">
      <li
        class="carousel-item  "
        :class="{ fade: index === currIndex }"
        v-for="(item, index) in sliders"
        :key="item.id"
      >
        <RouterLink to="/">
          <img :src="item.imgUrl" alt="" />
        </RouterLink>
      </li>
    </ul>
    <a href="javascript:;" class="carousel-btn prev" @click="toggle(-1)"
      ><i class="iconfont icon-angle-left"></i
    ></a>
    <a href="javascript:;" class="carousel-btn next" @click="toggle(1)"
      ><i class="iconfont icon-angle-right"></i
    ></a>
    <div class="carousel-indicator">
      <span
        :class="{ active: currIndex === i - 1 }"
        v-for="i in sliders.length"
        :key="i"
        @mouseenter="currIndex = i - 1"
      ></span>
    </div>
  </div>
</template>

<script>
/*
1.图片切换
2.移入小点点要实现点击
3.左右点击切换
4.自动切换
5.鼠标移入停止自动切换移出继续自动切换
6.自动切换功能需要可以配置参数进行控制
*/
import { ref, watch } from 'vue'
export default {
  name: 'XtxCarousel',
  props: {
    sliders: {
      type: Array,
      default: () => [] // 如果是原始值,直接写,如果是引用值,()=>引用值
    },
    autoplay: {
      type: Boolean,
      // 轮播图自动播放
      default: true
    },
    duration: {
      type: Number,
      default: 3000
    }
  },
  setup (props) {
    const currIndex = ref(0) //当前索引
    //点击切换
    function toggle (step) {
      currIndex.value = currIndex.value + step
      if (currIndex.value >= props.sliders.length) {
        currIndex.value = 0
      } else if (currIndex.value <= -1) {
        currIndex.value = props.sliders.length - 1
      }
    }
    //自动切换
    let _interval = null
    function start () {
      clearInterval(_interval)
      if (!props.autoplay) {
        return
      }
      _interval = setInterval(() => {
        toggle(1)
      }, props.duration)
    }
    start()
    function stop () {
      clearInterval(_interval)
    }
    //侦听自动播放
    watch(
      () => props.autoPlay,
      newVal => {
        if (newVal) {
          start()
        } else {
          stop()
        }
      },
      {
        immediate: true //初次侦听就执行回调函数
      }
    )
    return { currIndex, toggle, start, stop }
  }
}
</script>
<style scoped lang="less">
.xtx-carousel {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 150px;
  position: relative;
  .carousel {
    &-body {
      width: 100%;
      height: 100%;
    }
    &-item {
      width: 100%;
      height: 100%;
      position: absolute;
      left: 0;
      top: 0;
      opacity: 0;
      transition: opacity 0.5s linear;
      &.fade {
        opacity: 1;
        z-index: 1;
      }
      img {
        width: 100%;
        height: 100%;
      }
    }
    &-indicator {
      position: absolute;
      left: 0;
      bottom: 20px;
      z-index: 2;
      width: 100%;
      text-align: center;
      span {
        display: inline-block;
        width: 12px;
        height: 12px;
        background: rgba(0, 0, 0, 0.2);
        border-radius: 50%;
        cursor: pointer;
        ~ span {
          margin-left: 12px;
        }
        &.active {
          background: #fff;
        }
      }
    }
    &-btn {
      width: 44px;
      height: 44px;
      background: rgba(0, 0, 0, 0.2);
      color: #fff;
      border-radius: 50%;
      position: absolute;
      top: 228px;
      z-index: 2;
      text-align: center;
      line-height: 44px;
      opacity: 0;
      transition: all 0.5s;
      &.prev {
        left: 20px;
      }
      &.next {
        right: 20px;
      }
    }
  }
  &:hover {
    .carousel-btn {
      opacity: 1;
    }
  }
}
</style>
